Cooler weather finally returning

You can finally turn the AC down. The first major heat wave of summer is fading, allowing temperatures to slide back to normal along the coast and to more comfortable levels across inland foothills and valleys. A weak low pressure system is developing along the coast at the same time that the monsoon is losing strength. Daytime highs at Lindbergh Field in San Diego will be at or below normal Monday for the first time since August 26th. The normal high this time of year is 77.

There's also good news for football fans. The National Weather Service says that temperatures will be in the low 70s on Monday night when the Chargers open the season at home against Houston. The marine layer may creep in during the game, which begins shortly before 7:30 p.m. But winds will be light, out of the west.

Forecasters say that seasonal weather will linger at the coast through Thursday, but conditions could get unusually hot and humid again across the mountains and deserts as the monsoon cranks up, possibly for the last time this summer. A weather service advisory says, Some major changes may be in the offing for next week as we approach the autumnal equinox. The latest available global models show the westerlies across the eastern Pacific being forced farther to the south as a large trough develops off the Canadian coast. This could bring our first taste of fall weather sometime next week. Dry with max temps falling a bit below normal, and the end of the summer monsoon. So, the calendar may have it right this year."